The US reimposed tough sanctions on Tehran's energy and finance sectors last year but has granted Baghdad several exemptions to keep temporarily importing Iranian gas and electricity, crucial to Iraq's faltering power sector.

Abdel Mahdi, 77, has repeatedly said Iraq wants good ties with both the US and Iran.

The prime minister would spend two days in the Islamic republic, a member of his office told AFP on condition of anonymity because he was not authorised to speak to press.

He was expected to discuss "the issue of trade outside the framework of sanctions" in addition to "the rapprochement and the convergence of views between Iran and Arab countries", the official said.

Iran is the second-largest supplier of imported goods to Iraq and also enjoys vast political influence in the country, particularly among Iraq's Shiite parties.

Those factions credit Iran for helping Iraqi armed forces defeat the Islamic State group in a fierce three-year battle that ravaged much of the country.

Since declaring victory over IS in 2017, Iraq has strived to make a diplomatic comeback as a mediator among regional rivals.

A string of top officials have visited the Iraqi capital in recent months, including Iranian President Hassan Rouhani in March, US Secretary of State Mike Pompeo in January, and a host of Arab leaders.

During his weekly press conference on Tuesday, Abdel Mahdi said he was planning trips to Saudi Arabia, Turkey and the United States, without specifying dates.

The premier has rarely travelled since coming to power in October, making his first trip abroad in late March to Egypt.

There, he met Egyptian President Abdel Fattah al-Sisi and King Abdullah II of Jordan to discuss economic and security cooperation among the three countries.

Last month, Iraq's speaker of parliament Mohammed al-Halbusi travelled to the US, where he said his country would need to rely on Iranian gas and electricity for another three years.